1. Field of the Invention
This invention relates generally to gear changing mechanisms, and more particularly to a gear changing mechanism suitable for use with an automotive transmission incorporating an overdrive gearset or any two-speed gearset where it is acceptable to momentarily interrupt the power to change from one gear ratio to the other.
2. Description of the Prior Art
In recent years there have been many improvements in gear changing mechanisms, including improvements related to reversible overrunning clutches adapted for use in transferring torque through a power train in an automotive vehicle. Some of these gear changing mechanisms are adapted for unidirectional transmission of torque. Others, while capable of driving in two directions, generally require mechanical elements such as cams for shifting the direction of drive or for shifting from a drive position to a freewheel position.
Such gear changing mechanisms generally incorporate elaborate drive structure, including mechanical elements for effecting a change in position of sets of balls or rollers so as to shift drive ratios or shift between a drive ratio and a freewheel position within the mechanism itself. In addition, such mechanisms generally incorporate elaborate and complicated shift elements.
Accordingly, it is an object of this invention to meet the continuing need and desire in the art for improvements in gear changing mechanisms by providing an improved gear changing mechanism having means adapted to engage one of two inputs to drive an output. It may be used in an automotive transmission that now uses synchronizers to select various gear ratios, for example an overdrive consisting of a planetary gearset where the sun gear is locked to the planet carrier for direct drive and locked to the housing for overdrive.